EP3475581B1 - Gas turbine impeller hub fairing ring that is plastically deformable - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to a paddle wheel fairing ring, a paddle wheel equipped with such a fairing ring, and a turbomachine fitted with such a paddle wheel. In particular, the impeller can be a turbojet fan, but not only.

STATE OF THE PRIOR ART

The structures for sealingly delimiting the gas stream (ie the passage for gases) at the foot of the blade within an impeller generally comprise an inter-blade platform and a seal carried by each platform and in contact with dawn, especially at the leading edge and trailing edge of the blades. Such a structure is described in the document FR 2 987 086 .

However, the seal at the leading edge and / or the trailing edge of the blades, where the geometry is particularly complex, remains perfectible. There is therefore a need in this sense.

FR 2 918 409 discloses a fairing ring according to the preamble of claim 1. US 2011/037233 discloses a seal assembly. FR 3 010 442 discloses a one-piece blading disc with reduced stresses at the root of the blade, preferably for an aircraft turbomachine blower.

PRESENTATION OF THE INVENTION

One embodiment relates to a paddlewheel fairing ring as defined by claim 1, comprising an axially extending annular wall, said wall having a plurality of axially extending notches, each notch being configured to receive a leading edge or trailing edge of a dawn.

By “extends axially” it is understood of course that the element in question extends strictly parallel to the axial direction, or else by making an angle less than 45 ° with the axial direction. Thus, within the meaning of the present description, a frustoconical annular wall extends axially.

It is understood that the ring extends in an axial direction, a radial direction and a circumferential direction. In general, the axial direction corresponds to the direction of the axis of rotation of the impeller (or direction of the axis of the fairing ring), and a radial direction is a direction perpendicular to the axial direction. The circumferential direction corresponds to the direction describing a ring around the axial direction. The three directions axial, radial and circumferential correspond respectively to the directions defined by the coast, the radius and the angle in a cylindrical coordinate system.

It is also understood that the notches are all arranged on the same side of the ring considered in the axial direction.

Thus, by placing the ring around the leading or trailing edges of the blades of an impeller by accommodating each leading or trailing edge in a notch, one reliably delimits a gas passage without possible leakage. between each blade and the fairing ring, respectively at the inlet or outlet of the impeller. Of course, the leading edges of the blades are arranged on the inlet side (or upstream) of the impeller while the trailing edges of the blades are arranged on the side of the outlet (or downstream) of the impeller blades.

In certain embodiments, each notch has a shape of leading edge or trailing edge profile of a blade.

Such a notch shape allows the ring to best match the shape of the blades, whereby the seal is improved.

The inter-notched parts are made of composite material while the rest of the ring is made of metallic material.

A composite material is an assembly of at least two different immiscible materials, while a metallic material is a metal or a metal-based alloy.

The inter-notch parts are of course the parts of the ring which extend between two adjacent notches. For example, the inter-notch parts are made of polyurethane foam or a honeycomb structure with a honeycomb body of aluminum or poly (m-phenyleneisophthalamide) (also known under the generic commercial name Nomex®) covered with a metallic layer (or skin) (for example titanium or aluminum) or carbon fiber composite. For example, the rest of the ring is made of titanium or aluminum.

When a blade is deformed, for example in the event of ingestion of a solid element (for example a bird), it can come into contact against an inter-notch part and deform this inter-notch part in the circumferential direction. This contact makes it possible to relieve the dawn and limit the deflections thereof thereby limiting the possible damage in the dawn. In addition, for the most critical events such as ingestion of a heavy bird or loss of dawn, contact is not enough to limit damage in the dawn. In that case, allowing plastic deformations of the inter-notch parts ensures energy dissipation from the blade to the inter-notch parts, thereby limiting dawn damage. Such a combination of composite material for the inter-notched parts and metallic material for the rest of the ring allows the designer to precisely adjust the stress threshold from which the inter-notched parts are plastically deformed (ie the plasticity threshold ).

In certain embodiments, each inter-notch part is configured to deform plastically when it is subjected to a circumferential force greater than or equal to 40 kN ± 30% (forty kilo-Newtons plus or minus thirty percent).

It is thus ensured that beyond a predetermined imposed displacement, generating such a circumferential force, the inter-notch part adjacent to a blade which deforms with a large amplitude deforms plastically. This allows this inter-notch part to provide an energy dissipator function, whereby energy is dissipated from the deformation of the blade and the amplitude of deformation of the blade is limited. This limits the propagation of deformations within the dawn.

In some embodiments, the fairing ring includes at least one wear portion configured to be disposed vis-à-vis a blade.

It is understood that a part of wear is a part configured to wear for the benefit of another part in contact, in this case a blade. Of course, a wear part is generally removably mounted so that it can be replaced when the wear of said wear part is too great. For example, a seal can form a wear part.

For example, the surfaces of the ring delimiting the notches are equipped with a wear part. Thanks to such a wear part, the fairing ring can be mounted in contact with the leading or trailing edge of the blades, thanks to which the sealing is maximum, while the wear part ensures, in wear and tear with use, the integrity of the blades.

In some embodiments, the fairing ring includes a radially extending annular wall configured to mount said fairing ring on an impeller disc.

Such a radial annular wall makes it possible to offset all the means for mounting the fairing ring on a paddle wheel, for example the holes, tappings, hooks, etc., on a part of the ring which is not intended to delimit a gas passage. This ensures a better seal.

In some embodiments, the fairing ring is configured to be equipped with a paddle wheel inlet or outlet cone.

Such a paddle wheel inlet or outlet cone makes it possible to guide the flow of gas entering or leaving the wheel.

One embodiment also relates to a paddle wheel equipped with at least one fairing ring according to any one of the embodiments described in the present description.

For example the impeller comprises a disc at the periphery of which are mounted a plurality of blades, and a plurality of inter-blade platforms, the inter-blade platforms being configured to leave the leading edge and / or the edge of leakage of free blades. Thus, the fairing ring follows the leading edges and / or the trailing edges (the impeller may comprise a single fairing ring placed at the inlet or at the outlet of the wheel, or two rings of fairing, one arranged at the entry and the other at the exit of the wheel). Thus, the leading and / or leaking edges are housed in the notches of the ring while the axial end of the inter-notched parts of the ring cooperates with the corresponding axial end of the inter-blade platforms.

In certain embodiments, the inter-notched parts of the fairing ring extend over a maximum of 15% of the axial length of the blades.

The length of the blades is measured in projection in the axial direction. By configuring the notches so that the blades are received over 15% of their length from their leading or trailing edge, it is ensured that the fairing ring covers the parts of the blades having the most complex and most geometry difficult to seal. Such a configuration thus makes it possible to optimize the seal between the blades and the fairing ring.

An embodiment also relates to a turbomachine equipped with an impeller according to any one of the embodiments described in the present description.

Such impellers are particularly well suited for implementation within a turbomachine. For example, one embodiment relates to a turbojet while said impeller forms the fan of said turbojet.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente un turboréacteur présentant une soufflante,
• la figure 2 représente un anneau de carénage équipant la soufflante du turboréacteur de la figure 1,
• la figure 3 représente une vue partielle en perspective de la soufflante du turboréacteur de la figure 1 équipée de l'anneau de carénage de la figure 2, et
• la figure 4 représente une vue de côté de la soufflante partiellement assemblée.

The invention and its advantages will be better understood on reading the detailed description given below of different embodiments of the invention given by way of non-limiting examples. This description refers to the pages of attached figures, on which:

• the figure 1 represents a turbojet engine presenting a fan,
• the figure 2 represents a fairing ring fitted to the fan of the turbojet engine figure 1 ,
• the figure 3 shows a partial perspective view of the fan of the turbojet engine figure 1 equipped with the fairing ring of the figure 2 , and
• the figure 4 shows a side view of the partially assembled blower.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENT

The figure 1 represents a turbomachine 100, in this example a turbojet 100, comprising paddle wheel 80, in this example a fan 80, equipped, at the inlet, with a fairing ring 10 on which is mounted an inlet cone 50.

The fairing ring 10 extends in an axial direction X, a radial direction R and a circumferential direction C. The ring 10 has an axially extending annular wall 10A (or axial wall 10A) in which is formed a plurality notches 12. The ring 10 also has an annular wall 10B extending radially (or radial wall 10B). Of course, the axial wall 10A can form an angle between 0 ° and 45 ° with the axial direction X while the radial wall 10B can make an angle between 45 ° and 90 ° with the axial direction X.

The radial wall 10B has a first series of fixing holes 10B1 for fixing the ring 10 to the disc of the fan 80. The radial wall 10B has a second series of fixing holes 10B2 for fixing the cone 50 on the ring 10. Finally, the radial wall 10B has a third series of oblong holes 10B3. These holes 10B3 are provided to lighten the ring 10.

The notches 12 are all formed on the same side of the ring 10 in the axial direction X. Each notch 12 has the shape of the profile of the leading edge 82A of the blades 82 of the fan 80. As can be seen on the figure 3 , each notch 12 receives a leading edge 82A of a blade 82.

As shown in the figure 4 , the fairing ring 10 is mounted on a disk 83 of the fan 80, at the periphery of which the blades 82 are mounted, these blades 82 being inserted in the grooves 83A configured to receive the feet of the blades 82, and inter platforms -blades 84, these inter-blade platforms 84 being mounted on the teeth 83B of the disc 83.

In this example, the fairing ring 10 cooperates axially in contact with the inter-blade platforms 84 so as to continuously define a gas passage between the blades 82, at the foot of the blades 82. More particularly, in this example, the parts of the wall 10A of the ring 10 extending between the notches 12 form inter-notch parts 14 while the axial end of inter-notch parts 14 is in contact with the axial end opposite the inter-blade platforms 84.

The axial length L1 of the inter-notched parts 14 is in this example about 8% of the axial length L of the blades 82. Thus, in general, the inter-notched parts 14 extend over a maximum of 15% of the length axial L of the blades 82.

Furthermore, the surfaces of the inter-notch parts 14 each delimiting the notches 12, these surfaces being arranged opposite the blades 82, and more particularly the leading edge 82A of the blades 82, have a wear part. 12A in contact with the blades 82.

As is visible on the inter-notch part 14 shown in cutaway, each inter-notch part 14 has an internal honeycomb structure of poly (m-phenyleneisophthalamide), covered with a metallic coating in this example of titanium. The rest of the ring 10 is made of metal, in this example titanium.

Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention which is defined by the claims. In particular, the description and the drawings should be considered in an illustrative rather than restrictive sense.

Claims (9)

1. A fairing ring (10) for a bladed wheel (80), comprising an annular wall (10A) extending axially, said wall (10A) presenting a plurality of notches (12) extending axially, each notch (12) being configured to receive a leading edge (82A) or a trailing edge of a blade (82), characterized in that the inter-notch portions (14) are made of composite material, a composite material being an assembly of at least two different materials that are not miscible, while the rest of the ring (10) is made of metal material, a metal material being a metal or a metal-based alloy.
2. A fairing ring (10) according to claim 1, wherein each notch (12) presents the shape of the profile of a leading edge (82A) or of a trailing edge of a blade (82).
3. A fairing ring (10) according to claim 1 or claim 2, wherein each inter-notch portion (14) is configured to deform plastically when subjected to a circumferential force that is greater than or equal to 40 kN ±30%.
4. A fairing ring (10) according to any one of claims 1 to 3, including at least one wear portion (12A) configured to be placed facing a blade (82).
5. A fairing ring (10) according to any one of claims 1 to 4, including an annular wall (10B) extending radially and configured to mount said fairing ring on a disk (83) of the bladed wheel (80).
6. A fairing ring (10) according to any one of claims 1 to 5, configured to be fitted with an inlet or an outlet cone (50) of the bladed wheel (80).
7. A bladed wheel (80) fitted with a fairing ring (10) according to any one of claims 1 to 6.
8. A bladed wheel (80) according to claim 7, wherein the inter-notch portions (12) of the fairing ring (10) extend over not more than 15% of the axial length (L) of the blades (82).
9. A turbomachine (100) including a bladed wheel (80) according to claim 7 or claim 8.

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